McGill University: Research briefs: Predicting coma recovery, black carbon and lockdowns

Higher levels of air pollution in snowbound cities
Snowbound cities such as Montreal have higher concentrations of black carbon, a powerful air pollutant, than cities in warmer climates according to researchers Houjie Li and Professor Parisa Ariya of the Department of Atmospheric and Oceanic Sciences and the Department of Chemistry. This is because particles of black carbon produced by diesel and other fossil fuels are transferred to surfaces through snow and then re-emitted to the atmosphere. Consequently, the same carbon emission rates in a warmer city can produce a much higher concentration of pollutants in a colder city. In comparing two pollution hotspots in Montreal, the researchers also found that concentrations of black carbon were 400% higher at the Montreal airport than in downtown Montreal. The study also points out that air quality norms around the world do not take into account the fact that cold climate conditions pose a particular threat to public health. Interestingly, the research also shows that during the COVID-19 lockdown period which started in March 2020, concentrations of black carbon in downtown Montreal decreased up to 72%, revealing that human activities accounted for most air pollutants.

“Black Carbon Particles Physicochemical Real-Time Data Set in a Cold City: Trends of Fall-Winter BC Accumulation and COVID-19” by Houjie Li et al. was published in the Journal of Geophysical Research-Atmospheres.


Projecting climate change more accurately
Scientists have been making projections of future global warming using powerful supercomputers for decades. But how accurate are these predictions? Modern climate models consider complicated interactions between millions of variables. They do this by solving a system of equations that attempt to capture the effects of the atmosphere, ocean, ice, land surface and the sun on the Earth’s climate. While the projections all agree that the Earth is approaching key thresholds for dangerous warming, the details of when and how this will happen differ greatly depending on the model used. Now, researchers from McGill University, including Professor Shaun Lovejoy and Roman Procyk of the Department of Physics hope to change all that. Building on an approach pioneered by Nobel prize winner Klaus Hasselmann, they have developed a new way to measure climate change more accurately and precisely. Their new projections are based on equations that combine the planet’s energy balance and slow and fast atmospheric processes called “scaling”. This breakthrough opens new avenues of research on future and past climates on Earth, including ice ages. The new model can even be used to make precise regional temperature projections. By comparing their projections to the conventional ones used by Intergovernmental Panel on Climate Change, the researchers found that the new model gives overall support to the IPCC projections but with some significant differences. While the new model projects a crossing of the key thresholds for dangerous warming a bit later, the time frame for crossing it is much narrower. According to the researchers, there is a 50% chance of exceeding the 1.5C threshold by 2040.

“The Fractional Energy Balance Equation for Climate projections through 2100” by Roman Procyk et al. was published in Earth System Dynamics.



Herbicide Roundup disturbing freshwater biodiversity
As Health Canada extends the deadline on public consultation on higher herbicide concentrations in certain foods, research from McGill University shows that the herbicide Roundup, at concentrations commonly measured in agricultural runoff, can have dramatic effects on natural bacterial communities. “Bacteria are the foundation of the food chain in freshwater ecosystems. How the effects of Roundup cascade through freshwater ecosystems to affect their health in the long-term deserves much more study,” say the researchers.

“Resistance, resilience, and functional redundancy of freshwater bacterioplankton communities facing a gradient of agricultural stressors in a mesocosm experiment” was published in Molecular Ecology.


Mapping the genome of lake trout to ensure its survival
An international team of researchers from the U.S. and Canada, including researchers from McGill University, have managed to create a reference genome for lake trout to support U.S. state and federal agencies with reintroduction and conservation efforts. Lake trout, once the top predator fish across the Great Lakes, reached near extinction between the 1940s and 1960s due to pollution, overfishing, and predation by the invasive lamprey eel. Once showing striking levels of diversity in terms of size, appearance, and ability to adapt to varied environments, now the only lake trout populations to have survived are to be found in Lake Superior and Lake Huron. Genomes of salmonids, a family that includes lake trout, are harder to compile than those of many other animals, the research team said. “Between 80-100 million years ago, the ancestor of all salmonid species that lake trout belong to went through a whole genome duplication event. As a result, salmonid genomes are difficult to assemble due to their highly repetitive nature and an abundance of duplicated genomic regions with similar sequences,” explains Ioannis Ragoussis, the Head of Genome Sciences at the McGill Genome Centre, where the sequencing took place.

“A chromosome-anchored genome assembly for Lake Trout (Salvelinus namaycush)” was published in Molecular Ecology Resources.


Why do species live where they do?
As the climate changes, what factors will decide where species can survive and thrive? Scientists try to answer this question by studying what governs where species live today. Harsh and cold environmental conditions play a role, especially toward the poles like in Canada. But researchers Anna Hargreaves, an Assistant Professor in the Department of Biology and Alexandra Paquette show that interactions with other species – like competition and predation – are also major driving factors in determining where species can live, especially in warmer conditions toward the equator.

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